The invention relates to a Bowden cable, in particular, for a motor vehicle latch containing a locking mechanism comprising a catch and at least one pawl for locking the catch in a main ratchet position and in a pre-ratchet position, preferably with a closing aid for moving the catch from the pre-ratchet position to the main ratchet position. The invention also relates to a method for installing the Bowden cable.
A Bowden cable contains a Bowden cable core and a Bowden cable sheath. In most cases, the Bowden cable core is a steel cable or a wire cable. The Bowden cable sheath is generally a flexible but pressure-resistant sleeve, serving as a mechanical guide of the Bowden cable core and as a counter bearing for the tractive forces transferred by the Bowden cable core. Due to the flexibility of the Bowden cable, forces can also be transferred if the Bowden cable is bent. A Bowden cable can not only transfer a tractive force through the Bowden cable core but also a compressive force through the Bowden cable sheath in the same manner.
Such a Bowden cable is, for instance, used in motor vehicle latches with a closing aid, in order to provide an effective transfer of the forces or longitudinal movement of an actuator onto a closing pawl of a closing aid, able to move a locking mechanism from the pre-ratchet position to the main ratchet position or a motor vehicle door or flap connected to the locking mechanism between a respective pre-ratchet position and main ratchet position. Such an actuator for a closing aid for a motor vehicle door or flap moveable between a pre-ratchet position and main ratchet position is disclosed in printed matter DE 10 2011 108364 A 1.
For installation of the Bowden cable the Bowden cable is inserted and the ends of the Bowden cable core and of the Bowden cable sheath are connected to the connection parts. The Bowden cable sheath is regularly connected to the housing and the Bowden cable core to the connection parts, moveable in most cases.
Once installed and connected to the housing and/or connection parts, the Bowden cable normally has a certain play. Play refers in this instance to an unwanted difference in length, in relation to the desired state, between the Bowden cable core and/or the Bowden cable sheath or an unwanted relative positional difference between the Bowden cable core and Bowden cable sheath.
An excessive positive play would during later use interfere with the transmission of the force or longitudinal movement. Upon introduction of a force or movement in the Bowden cable, initially only the positive play would be reduced, so that the transfer of the force or movement at the other end will only occur after a delay. But also a negative play, i.e. a reduction in length in case of, for instance, a too short Bowden cable core, could adversely affect the subsequent function or capability. A too short Bowden cable core could result in a moveable connection part not being able to assume its intended position, the service life being reduced due to excessive stressing or wear to increase due to the friction between the Bowden cable sheath and Bowden cable core in tight radii of the Bowden cable.
During installation, the Bowden cable is generally adjusted in an additional work step, i.e. the play of the Bowden cable is reduced to a range of a mostly specified installation tolerance in relation to the target state. Once the Bowden cable has been adjusted, the settings of the Bowden cable, i.e. the length and length ratios of the Bowden cable sheath and Bowden cable core are fixed.
In particular in a Bowden cable with a positive connection to a connection part, e.g. by engaging a hook or a nipple, installation play must be provided to form the connection or connections. Installation play refers to play of the Bowden cable provided temporarily for the purpose of installation, without which a hook at the end of a Bowden cable core cannot be engaged. After the completed installation, the Bowden cable is re-set or tensioned in order to remove the installation play.
The tensioning direction of a Bowden cable is the direction in which the lengths and/or relative position of the Bowden cable sheath and/or Bowden cable core have to be changed in order to achieve a positive play.
In order to adjust and/or fix a Bowden cable during installation, a threaded or clamp connection is usually provided, with the aid of which the length of the Bowden cable sheaths or Bowden cable core can be adjusted and/or fixed.
In case of a threaded connection, e.g. for connecting a Bowden cable sheath to the housing, the thread pitch changes the length with each revolution and the self-locking effect of the thread for fixing.
In a clamp connection, for instance for connecting a Bowden cable core to a connection part, the desired length of the Bowden cable core is set and fixed by clamping to the connection part.
Printed matter DE 10110516 A1 discloses a connection mechanism formed by the Bowden cable for coupling a door latch to an internal locking button. Two parallel sections 76, 77 of a Bowden cable tube 7 are fixed in a mount 31. The mount 31 can be slid in longitudinal direction for setting the longitudinal position in a guide or support element 32. Symmetrically formed detent cogs 36 and a detent hook 37 ensure the fixing of the mount 31.